<P> Detailed Nd isotopic mapping in the southwestern Grenville Province between North Bay, Ontario, and Temiscaming, Quebec has revealed the precise trend of the proposed Penokean-aged suture discovered during reconnaissance isotopic mapping by Dickin and McNutt (1989). </p> <p> Lithotectonic domains proposed by Easton (1989} for the greater North Bay area are cross-cut by the suture. As presently located, the Tilden-Tomiko domain boundary effects no apparent offset of the suture which would be expected during low angle differential Grenville thrusting. Although a lack of apparent offset suggests these domains are not significant Grenville structures a definitive answer must await more precise mapping of their boundaries. There appears to be some potential for unravelling aspects of Grenville tectonism through such cross-cutting relationships. </p> <p> In the North Bay-Temiscaming area the full model age transition from ca 1.90 Ga to ca 2.70 Ga is negotiated in stepwise fashion through metasediments of intermediate Nd model age spanning an area from a few kilometers to a few tens of kilometers in width. This suggests the suture boundary is better described as a suture zone. Presently two groups of intermediate aged metasediments are recognized (1} a 2.00-2.39 Ga group and ( 2) a 2. 40-2.60 Ga group. These age groups correspond to rocks of two different lithologies separated along strike of the suture in the Temiscaming and North Bay areas respectively. Although the ages of metasediments comprising the suture zone more or less spans the entire interval between 1.90 and 2.70 Ga, there is no well defined transect wherein the whole range of intermediate aged crust is recorded within a single rock type. Therefore a 'splitting' rather than 'lumping' approach is deemed justified for the intermediate aged crust until provenance studies using zircons can be undertaken to show in a definitive manner whether or not the two groups are related in a genetic sense. </p> <p> The absence of plutonism with crystallization ages between 2.00 and 2.60 Ga in the North Bay-Temiscaming area suggests that metasediments of the suture zone acquired their model age from sedimentological mixing between crust of Archean (ca 2.70 Ga) and Proterozoic (ca 1.90 Ga) provenance. The arrangement of mixed provenance metasediments coincident with the suture suggests a genetic relationship. It is proposed that the mixed provenance metasediments are part of a foreland basin assemblage which formed in response to downloading of the cratonal edge by the combined effect of an overriding island arc and the attempted subduction of the Superior craton. </p> <p> Major element analyses show that mixed provenance and arc derived sediments of the proposed foreland basin display a wide range in their maturity. This is consistent with the foreland basin environment where sediments can be reworked to varying degrees in response to tectonically controlled local sea level fluctuations. Contrasting the dynamic environment of the foreland basin the belt of Archean crust north of the suture with model ages of ca 2.72 Ga shows a very restricted range of reworking implying a uniform depositionary environment e.g., deep water passive margin. </p> <p> North of the field area a lobe of Archean crust extends into the Grenville Province, anchored by the Pontiac Group on the northern margin of the Grenville Front (GF), and consisting in part of the parautocthonous Red Cedar Lake Gneiss south of the GF. The full expression of the Archean lobe within the Grenville Province and north of the North Bay Temiscaming field area is unknown, however, preliminary results from Nd isotopic mapping suggest that Archean crust between the suture and the Grenville Front Tectonic Zone (GFTZ) may be part of, or, derived from this Archean parautocthonous lobe. Archean provenance crust north of the field area defines a relatively homogeneous belt of crust with ca 2.72 Ga model ages and a whole rock Sm-Nd isochron age of 2.77 Ga. This is in sharp contrast to the heterogeneity of model ages displayed by Archean crust further west, between the suture (French River area) and the Grenville Front near Sudbury, Ontario (Dickin et al., 1989). Here, the Archean foreland may owe its peculiar heterogeneity to mixing between 2. 72 Ga crust and 2. 4 Ga Huronian volcanics andjor 1. 7 Ga Kilarnian juvenile crust (Dickin et al., 1990). Evidence for the presence of these crustal endmembers in the North Bay Temiscaming area is lacking. </p> <p> Finally, the presence of a suture zone consisting of mixed provenance metasediments is the best evidence yet in support of the suture hypothesis explanation for the model age transition as opposed to juxtaposition of two crustal age domains by Grenville thrusting. </p> / Thesis / Bachelor of Science (BSc)

<p> New U-Pb ages from the Barberton Mountain Land document an 800 m.y. period of Archean magmatism (ca. 3540 Ma to ca. 2740 Ma) that can be divided into five distinct episodes. Magmatic activity during Episode I includes tonalite-trondhjemite gneisses such as the Steynsdorp pluton (3509 +8/-7 Ma) and a tectonically interleaved sliver (3538 +4/-2 Ma) located at the base of the Onverwacht Group. Trondhjemitic magmatism of Episode II is synchronous with volcanism and inferred D1 thrusting of the Onverwacht Group and is represented by plutons such as the Doornhoek (3448 ± 4 Ma), Theespruit (3443 +4/-3 Ma), and Stolzburg (3459 +5/-4 Ma). A quartz-feldspar porphyry dyke, related to Episode II, intrudes the Komati Formation of the Onverwacht Group and yields an age of 3467 +12/-7 Ma. D2-related thrusting, volcanism, sedimentation, and tonalitic plutonism in the north-central part of the Barberton greenstone belt (BGB) occurred during Episode III and are recorded by an ignimbrite which was deposited between the Fig Tree and Moodies Groups during regional deformation (3227 ± 1 Ma), by pre- and post-tectonic porphyries (3227 Ma), and by the emplacement of the Kaap Valley tonalite (3227 ± 1 Ma). Episode IV is characterized by the intrusion of large sheet-like potassic batholiths to the north and south of the BGB and syenitic plutonism at ca. 3107 Ma, and by D3-related deformation at the northern margin of the BGB. Gold mineralization also appears to coincide in time with this episode. The last known period of Archean magmatic activity in the BGB is represented by late phase granite magmatism at ca. 2740 Ma (Episode V).</p> <p> Epsilon Nd values range from +1.3 to -0.7 in rocks varying in composition from gabbro to granodiorite that were emplaced during Episodes I to IV. A gabbro from the Komati Formation, with a baddeleyite age of 3352 +6/-5 Ma, has an ϵNd of +1.3, which is the only value to fall on a depleted mantle growth curve. This value is similar to ϵNd data obtained by others for ca. 3450 Ma basalts from the Onverwacht Group. Three Episode IV plutons have identical ϵNd values of -0.5, and a granite pluton from Episode V has an ϵNd of -4.3, indicating a source compatible with remelting of older crust.</p> <p> In summary, the protracted evolution of the Barberton Mountain Land occurred in a series of discrete events widely separated in time. Each event is characterized by a number of geological processes (magmatism, volcanism, sedimentation) that appear to coincide in time with thrust-related deformation as a result of compressional tectonics. The duration of the main period of crustal growth occurred over ≈365 m.y. from ca. 3470 Ma, with the formation of the main Onverwacht sequence and its associated tonalitic-trondhjemitic rocks through ca. 3230 Ma, with the intrusion of the Kaap Valley tonalite and D2 thrust-related deformation, to ca. 3105 Ma, with the widespread emplacement of sheet-like potassic batholiths bordering the Barberton greenstone belt.</p> / Thesis / Master of Science (MSc)

Isotopic abundances of the elements xenon, cesium, barium, cerium, neodymium, samarium, rubidium and strontium formed in the fast (fission spectrum) neutron fission of u^238 have been measured using the mass spectrometric method. These ratios were normalized 'With respect to each other through isobaric nuclides and isotope dilution to obtain the relative yields of isobaric chains in the heavy mass region. By normalizing the heavy mass yields to 100%, the absolute fission yields of twenty-one isobaric Chains in the 130 - 154 mass range were determined. The origin of the fine structure in the cumulative yield versus mass curve is discussed. It has been concluded that, while most of the fine structure arises from the variation in neutron emission probabilities, some of it could be the result of the shell effect in the fission process itself. / Thesis / Doctor of Philosophy (PhD)

<p> The results of an investigation of the electronic absorption spectrum of carbon diselenide are presented. The synthesis of the compound from individual isotopes of selenium is described.. Some new observations and results from a reinvestigation of the infrared and Raman spectra are reported. The electronic absorption spectra of individual isotopic molecules were recorded and a detailed vibrational analysis of one of the observed systems in the spectrum has been made o The rotational structure of bands in this system has been examined. A preliminary study of two other systems are discussed. The spectra of carbon diselenide and the analogous carbon disulphide are compared and the similarity between the two spectra is shown. </p> / Thesis / Doctor of Philosophy (PhD)

<p> The spectra of depolarized light scattered from Isotropic and anisotropic liquids were Investigated In order to obtain information on both the reorientational and collisional motions of the liquid molecules. </p> <p> The liquid spectra taken at 22°C on a Coderg spectrometer (1 cm. ^-1 slits) were decomposed into relaxational and collisional components using least squares fitting techniques. Integrated Intensities and depolarization ratios in the zero em -1 (1 cm ^-1= 3 x 10^10 hz.) frequency sjift region as well as in the less than 5 cm^-1 region are reported. </p> <p> The Isotropic liquid spectra from 5 cm ^-1 consisted of a narrow Lorentz and a broader coliisional component which was exponential at shifts > 10 cm^-1. The anisotropic spectra also consisted of relaxational and collisional components; however, the Integrated Intensity of the relaxational and the collisional components Increased by a factor of 20 and 10 respectively from the isotropic liquids. </p> <p> A simple model based on frame distortion Induced anisotropy was constructed to predict the relative Intensity ratios of the collisional component for both Isotropic and anisotropic liquids. </p> <p> The relaxation time of the Lorentz component was Interpreted for both isotropic and anisotropic liquids as being the average time between collisions. It was, found to vary as μ^((3/4)/p), where μ is the reduced mass of two colliding molecules and p the liquid density.</p> <p> The line width parameter 1/vo for all the collisional components was interpreted as being a measure of the duration of a collision and was found to vary as μ^1/2 independent of the density P. </p> / Thesis / Master of Science (MSc)

<p> Recent investigations by H. G. Thode, J. Macnamara and C. Collins have shown that the S^32/S^34 ratio in natural sulfur-containing compounds varies by as much as five percent. These wide-spread variations suggest that fractionation of the sulfur isotopes occurs in natural processes due to differences in the chemical properties of isotopic molecules. In order to determine the magnitude of the effects that could be expected, partition function ratios for isotopic molecules containing sulfur and equilibrium constants for many isotopic exchange reactions involving sulfur have been calculated by methods of statistical mechanics. The results of these calculations are discussed. </p> / Thesis / Master of Science (MSc)

No description available.

The isotopic composition of meteorite sulphur and sea water sulphates was investigated by means of a simultaneous collection mass spectrometer. It was found that sixteen samples of meteorite sulphur possessed identical isotope abundances within the precision of the instrument. The sulphates from various depths in the Atlantic, Pacific and Arctic Oceans, were found to be enriched in s34 compared to the meteorite base level. The overall variation in s32/s34 content was 0.39 percent for the sea water samples. / Thesis / Master of Science (MS)

This thesis is missing either page 57 or 58. The other copies of this thesis do not have this page either. -Digitization Centre / This study is an investigation of two regions which were once part of the same Proterozoic margin: the Frontenac Axis in the Southeastern Grenville Province of Ontario, and the island of Islay in Scotland. Shieh (1985) performed an oxygen isotopic study on the granitic plutons and surrounding metasediments in the Frontenac terrane. For the granites south of the Rideau Lake Fault, he observed extremely high 18O/16O ratios of +14.0%o (relative to SHOW), whereas north of the fault, the plutons gave ratios of around 10%o. Five of the plutons in Shieh's study have been dated using U-Pb zircon geochronology, with the following results: Battersea -1165 ± 3 Ma, Lyndhurst -1166 ± 3 Ma, Perth Road -1166 ± 3 Ma, Crow Lake -1176 ± 2 Ma, and Westport -1076 ± 2 Ma. The zircon ages are younger than the depleted mantle Nd model ages obtained (1211 to 1480 Ma) and signify that the plutons may be derived from a mantle source with contamination by the older surrounding metasediments which have an average Nd model age of 1790 Ma. Correlation between initial Nd (ENd(t) from +1 to +3) and initial Sr (Esr(t) from +9 to +21) also shows a mixed origin for the plutons. However, oxygen isotopes show that contamination by marble may also have occurred. Two features distinguish the Frontenac terrane southeast of the Rideau Lake Fault (RLF) from the Central Metasedimentary Belt (CMB) to the northwest: 1) the anorogenic (i.e. within plate) chemical signatures of the plutons, which are similar to the Hid-Proterozoic anorogenic granites that occur throughout North America (Anderson, 1983); and 2) the unique zircon ages for the plutons south of the RLF (1166 to 1176 Ha) that occur nowhere else in the CMB. This implies that the two areas define different crustal terranes. However, since Penokean (ca. 1800 Ha) crustal extraction ages are found in both terranes they may represent displaced segments of a single Penokean continental margin. In Scotland, a gneiss terrane on Islay was always inferred to be part of the Archean Lewisian complex. However, isotopic evidence shows that the Islay terrane is early Proterozoic in age (1782 Ha by U-Pb zircon geochronology) and that it is juvenile mantle-derived material, not a reworking of Archean crust during the Proterozoic. As a result, two major implications for the crustal evolution of Northern Britain are: 1) the Grampian terrane, an area directly adjacent to the newly defined Proterozoic Islay block, is probably underlain by Proterozoic basement; and 2) Northern Britain can be included in the Lower Proterozoic reconstruction of the Laurentian Shield. The similar crustal extraction ages observed in the Grenville of Ontario and on Islay give proof that these areas were part of a major 1.8 to 1.9 Ga crustal formation event, stretching from the southwestern U.S. to Finland. / Thesis / Master of Science (MS)

The use of nitrogenous fertilizers in agricultural and forestry practices coupled with increased fossil fuel combustion and resulting nitrogen (N) deposition across the landscape have contributed to a near doubling of N inputs to terrestrial ecosystems.  With such dramatic changes have come adverse environmental consequences including the acidification of soil and water resources and an increased rate of biodiversity loss in both flora and fauna.  A method of rapidly predicting ecosystem susceptibility to N loss across large spatial scales would facilitate the identification of those systems most likely to contribute to potentially adverse environmental impacts.  To begin the development of such a framework, this research utilizes study sites located throughout the geographic ranges of Douglas-fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda) to explore relationships between hyperspectral remote sensing, N stable isotope ratios ("15N) and growth response to nitrogenous fertilizer.  In both species multiple linear regression models relating leaf-level reflectance to "15N showed strong predictive capabilities, with some models explaining more than 65% of the variance in "15N.  Significant correlations between "15N metrics and growth response to N fertilization were also observed in both species.  Additional exploratory analysis of the inclusion of "15N metrics with other environmental and edaphic variables to predict fertilizer growth response showed an increase in model performance with the addition of the enrichment factor (EF ="15NFol - "15NSoil).  This research demonstrates the ability of hyperspectral reflectance to predict "15N and reveals the potential of "15N to be included in future models to predict fertilizer growth response. / Master of Science